We investigated the effect of varying the level of cooperation in a smart charging agent (SCA) on user perception and behavior. Our study involved manipulating the SCA’s cooperativeness by varying its degree of automation and the amount of information sharing with the user and measuring effects on changes in user behavior, perceived goal alignment, the user’s awareness of the SCA’s information processing, and perceived cooperativeness. Our hypothesis that a lower degree of automation of the SCA would increase human-agent cooperation was not supported by our results. Instead, participants in the high-automation condition chose a later charging endpoint more often, implying greater cooperation. Our hypothesis that a higher amount of information shared by the SCA would increase human-agent cooperation was only partially confirmed. Cooperation led to a more positive user experience, but the correlation was only moderate to strong. The study shows the limitations of using the degree of automation as a sole measure of human-machine cooperation and highlights the need to explore other operationalizations of human-machine cooperation. Further research is needed to explore other scenarios and variations in the information provided to the user to better understand human-machine cooperation in the context of smart charging.